Support additional kernel packages

Author: trungleduc

README.md

@@ -61,3 +61,15 @@ npm run start:bash # Open a bash shell in the container
 #.env file
 JUPYTERLITE_EXTERNAL_MY_CUSTOM_EXTENSION=../demo/my-custom-ext
 ```
+
+- To install additional packages to the kernel enviromnent, create `jupyterlite/environment.yml` file with following content:
+
+```yaml
+name: xeus-build-wasm
+channels:
+  - https://repo.mamba.pm/emscripten-forge
+  - conda-forge
+dependencies:
+  - package-1
+  - package-2
+```

script/build.sh

@@ -1,4 +1,5 @@
 #!/bin/bash
+set -e
 
 echo "############## INSTALLING EMPACK ##############"
 cd  /home/$MAMBA_USER/empack
@@ -43,5 +44,8 @@ cd /home/$MAMBA_USER/xeus
 rm -fr tsconfig.tsbuildinfo
 python -m pip install -e . -v --no-build-isolation
 cd $LITE_DIR
+if [ -f ./environment.yml ]; then
+  micromamba install -n $WASM_BUILD_ENV --platform=emscripten-wasm32 -f ./environment.yml --yes
+fi
 rm -fr _output .jupyterlite.doit.db
 jupyter lite build --XeusAddon.prefix=$PREFIX --XeusAddon.mounts=$PREFIX/lib/python3.11/site-packages/pyjs:/lib/python3.11/site-packages/pyjs

script/wasm-env.yaml

@@ -10,6 +10,7 @@ dependencies:
   - pybind11_json
   - bzip2
   - zlib
+  - zstd
   - sqlite
   - libffi
   - exceptiongroup
@@ -19,4 +20,3 @@ dependencies:
   - requests-wasm-polyfill>=0.3.0
   - libpython
   - numpy
-